1. Field of the Invention
The present invention generally relates to a semiconductor device using compound semiconductors and a method of fabricating such a compound semiconductor device. More particularly, the present invention relates to improvements in the off-state breakdown characteristics.
2. Description of the Related Art
There are known, as compound semiconductor devices, a MESFET (Metal Semiconductor Field Effect Transistor) and a HEMT (High Electron Mobility Transistor). Among the field effect transistors (FETs) mentioned above, the high-power type of FETs is required to have a sufficient off-state breakdown voltage.
An object of the present invention is to provide a semiconductor device having a novel layer arrangement that enables improvements in the off-state breakdown characteristics and a method of fabricating such a device.
The above object of the present invention is achieved by a compound semiconductor device including: a gate electrode, a drain electrode, and a source electrode; and a p-type semiconductor layer provided between the gate electrode and the drain electrode, the p-type semiconductor layer having a lower acceptor concentration on a drain side thereof than that on a gate side thereof.
The above object of the invention is also achieved by a method of fabricating a compound semiconductor device comprising the steps of: (a) growing an epitaxial substrate; and (b) forming a p-type semiconductor layer provided between a gate electrode and a the drain electrode formed on the epitaxial substrate, the p-type semiconductor layer having a lower acceptor concentration on a drain side thereof than that on a gate side thereof.